The Atlantic Wolf-fish (Anarhichas lupus), is a marine fish, the largest of the wolf-fish family. The numbers of the Atlantic wolffish are rapidly depleting due to overfishing and by-catch, and is currently a Species of Concern according to the National Oceanic and Atmospheric Administration's (NOAA) National Marine Fisheries Service (NMFS). Although it is a fearsome looking creature, the Atlantic wolffish is only a threat when defending itself outside of the water. Apart from their unique appearance wolffish are also distinguished by the natural antifreeze they produce to keep their blood moving fluidly in their very cold habitat, involvement by both the male and female in brood bearing, and the large size of their eggs. Wolffish population success is also an important indicator of the health of other bottom dweller populations, such as cod.
Wolf-fish - S.Mackintosh
Description[]
In spite of its large size the Atlantic wolffish has retained the bodily form and general external characteristics of small blennies. The largest specimen recorded measured 150 cm (almost 5 ft) long and weighed almost 18 kg (40 lbs). Its body is long, subcylindrical in front, compressed in the caudal portion, smooth and slippery, the rudimentary scales being embedded and almost hidden in the skin. Atlantic wolffish vary in color, usually seen as purplish-brown, a dull olive green, or blueish gray. An even dorsal fin extends the whole length of the back, and a similar fin from the vent to the caudal fin, as in blennies. The pectorals are large and rounded and the pelvic fins are entirely absent. Its obtuse eel-like body type makes the fish swim slowly, undulating from side to side, like an eel.
The Atlantic wolf-fish's distinguishing feature (and from where it gets its common name) is its extensive teeth structure. Both the lower and upper jaw are armed with four to six fang-like, strong conical teeth. Behind the conical teeth in the upper jaw, there are three rows of crushing teeth. The central row has four pairs of molars and the outer rows house blunted conical teeth. The lower jaw has two rows of molars behind the primary conical teeth. The wolffish's throat is also scattered with serrated teeth.
Range and Habitat[]
The Atlantic wolffish are primarily stationary fish, rarely moving from their rocky home. They are benthic dwellers, living on the hard ocean floor, frequently seen in nooks and small caves. They like cold water, at depths of 76 to 120 meters (250 to 400 ft). They are usually found in waters of 34-36°F (1-2°C) and sometimes as low as 30°F (-1°C). Since they live in nearly freezing waters, in order to keep their blood moving smoothly, their blood contains a natural antifreeze.
Atlantic wolf-fish are inhabitants of the northern seas of both hemispheres, being common on the coasts of Scandinavia and North Britain, and also in the seas around Iceland and Greenland.
Diet[]
Atlantic wolffish use their strong jaws to eat hardshell mollusks, crustaceans, and echinoderms. They do not eat other fish. They are known to frequently eat large welks, sea clams, large hermit crabs, starfish and sea urchins. They are an important predator of sea urchins, whose populations escalate rapidly and can negatively effect the health of a marine system.
Reproduction[]
The manner of which Atlantic wolffish fertilize their eggs distinguishes them from many fish. Instead of the female depositing her eggs in the open ocean for the male fish to fertilize and then continue on his way, they are internally fertilized and the male wolf-fish stays with the nest and protects the eggs for as long as four months, until the brood is strong enough to gain independence. Their eggs are 5.5–6 mm in diameter, (among the largest fish eggs known), yellow tinted and opaque. The eggs are laid on the ocean floor, many times in shoal water, sticking together in loose clumps, surrounded by seaweed and stones. Altantic wolf-fish mature relatively late, at age six.
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